如何查看 docker-compose 健康检查日志？

Question

在我docker-compose.yml ，我有以下service healthcheck部分。 我想知道 MariaDB 是否真的准备好处理查询。 名为cmd的service配置为依赖于condition: service_healthy 。

  db:
    image: mariadb:10
    environment:
      MYSQL_RANDOM_ROOT_PASSWORD: 1
      MYSQL_USER: user
      MYSQL_PASSWORD: password
      MYSQL_DATABASE: database
    healthcheck:
      test: ["CMD", "mysql", "--user=user", "--password=password", "--execute='SELECT 1'", "--host=127.0.0.1", "--port=3306"]
      interval: 1s
      retries: 30

此健康检查不起作用，表明服务不健康。

如何检查test CMD 的输出？

Answer 1

您可以使用：

docker inspect --format "{{json .State.Health }}" <container name> | jq

输出：

{
    "Status": "unhealthy",
    "FailingStreak": 63,
    "Log": [
        {
            "Start": "2017-03-11T20:49:19.668895201+03:30",
            "End": "2017-03-11T20:49:19.735722044+03:30",
            "ExitCode": 1,
            "Output": "ERROR 1064 (42000) at line 1: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near ''SELECT 1'' at line 1\n"
        }
    ]
}

并寻找输出部分。

仅获取输出：

docker inspect --format "{{json .State.Health }}" mariadb_db_1 | jq '.Log[].Output'

对于群模式，请使用以下格式（感谢@shotgunner 指出）：

{{json.Spec.TaskTemplate.ContainerSpec.Healthcheck}}

随意将jq换成您用于 json 漂亮打印的任何工具。

Answer 2

docker-compose ps将指示每个服务的状态，如果定义了健康检查，则包括其健康状况。 这是一个基本的概述。

% docker-compose ps
                Name                                Command                       State                                       Ports                            
----------------------------------------------------------------------------------------------------------------------------------------------------------------
remix-theme-editor_analytics_1            /bin/sh -c /analytics/run. ...   Up                                                                                   
remix-theme-editor_base_1                 /bin/bash                        Exit 0                                                                               
remix-theme-editor_flower_1               /entrypoint --environment  ...   Exit 137                                                                             
remix-theme-editor_frontend_1             /bin/sh -c perl -p -i -e ' ...   Exit 137                                                                             
remix-theme-editor_js-app_1               npm run                          Exit 0                                                                               
remix-theme-editor_mq_1                   docker-entrypoint.sh rabbi ...   Up (healthy)            15671/tcp, 15672/tcp, 25672/tcp, 4369/tcp, 5671/tcp, 5672/tcp
remix-theme-editor_mysql-migration_1      /entrypoint_mysql-migratio ...   Exit 0                                                                               
remix-theme-editor_mysql_1                /bin/sh -c /entrypoint_wra ...   Up (health: starting)   127.0.0.2:3308->3306/tcp                                     
remix-theme-editor_page-renderer_1        npm run start:watch              Up                                                                                   
remix-theme-editor_python-app_1           /entrypoint                      Exit 2                                                                               
remix-theme-editor_redis_1                docker-entrypoint.sh /bin/ ...   Up (health: starting)   6379/tcp                                                     
remix-theme-editor_scheduler_1            /entrypoint --environment  ...   Exit 137                                                                             
remix-theme-editor_socket_1               /entrypoint --environment  ...   Exit 1                                                                               
remix-theme-editor_static-builder_1       npm run watch                    Up                                                                                   
remix-theme-editor_static-http_1          nginx -g daemon off;             Up                      127.0.0.2:6544->443/tcp, 80/tcp                              
remix-theme-editor_web_1                  /entrypoint --environment  ...   Exit 1                                                                               
remix-theme-editor_worker_1               /entrypoint --environment  ...   Exit 1                                                                               
remix-theme-editor_worker_screenshots_1   /entrypoint --environment  ...   Exit 1     

如果您需要更多详细信息，请将docker inspect与docker ps -q <service-name> 。

% docker inspect --format "{{json .State.Health }}" $(docker-compose ps -q mq) | jq
{
  "Status": "starting",
  "FailingStreak": 48,
  "Log": [
    {
      "Start": "2018-10-03T00:40:18.671527745-05:00",
      "End": "2018-10-03T00:40:18.71729051-05:00",
      "ExitCode": -1,
      "Output": "OCI runtime exec failed: exec failed: container_linux.go:348: starting container process caused \"exec: \\\"nc\\\": executable file not found in $PATH\": unknown"
    },
...

您始终可以通过自己执行健康检查代码来自己调试健康检查。 例如：

% docker exec -it $(docker-compose ps -q socket) nc -w2 127.0.0.1 5672
(UNKNOWN) [127.0.0.1] 5672 (?) : Connection refused

你也可以在 shell 中做同样的事情：

% docker exec -it $(docker-compose ps -q socket) bash
root@b5da5207d344:~/src# nc -w2 127.0.0.1 5672
(UNKNOWN) [127.0.0.1] 5672 (?) : Connection refused
root@b5da5207d344:~/src# echo $?
1

最后，您可以简单地在第一个终端窗口中使用docker-compose up ，并在另一个终端窗口中使用docker-compose logs -f 。 这将显示来自 docker-compose-managed 容器的所有日志。